Clock



FIG. 1 is a front elevation view of a clock showing my new design;

FIG. 2 is a side elevation thereof taken from the right-hand side of FIG. 1;

FIG. 3 is a top plan view thereof;

FIG. 4 is a rear elevation thereof;

FIG. 5 is a side elevation taken from the left-hand side of FIG. 1; and

FIG. 6 is a bottom plan view thereof. 

The ornamental design for a clock, as shown and described. 